SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3624182006bcb48741e2b61e1eb507e18658d4d5b58f8dc3f3d27fa9b764b807' 
  AND token = 'iEIP4wB+IJ1JNcUEqdyBLSphIGc5cdSupMDDyeRoF9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}