SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f488fbd24f32fa269a5029cdb96728abdd0801ec4b535b3e09b49164aec9ea87' 
  AND token = 'd56B+DHlniVpLNKr+FBTmuhh1YLi1ds+pjW5QEy4EUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}