SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce214c2eda9ab51b00ddde5e5dfa7fa9970fcad7139bb627a3adc3002c90893' 
  AND token = 'QaUrSzJq/GA79GuNMwwWDeUN7gWqMDUgmpgJDlHOLRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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