SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba0961612ba7d3a1a0bedfc31cb2dcafb3696f3af5647a141721d6c75702fcde' 
  AND token = 'FA/HjmD5Fw3UQ3r9LizQtaBfPUYyjnPoo0vRDh3i3n0=' 
  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"
    }
  }
}