SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ffe3c7ab7b4f9ad06845abbcad5735b545a9e0bd4c48da06c49ad79bf77249a' 
  AND token = 'kEqt8c2hZ3Oru0iniasP9JClOhioM2VFEH2HQokuNsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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