SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77bb3a6d5295799920ea85fa29ad819320def9687c13784a0f9f01c966ea3cf3' 
  AND token = 'AMOrbDqeD76zVMNynwmjJ8GRzEi7GunM0uBV7ra13co=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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