SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd80fd597f069300a7cfd09ebf42474b43ca9f28866e889ee1217808cb615123e' 
  AND token = 'OMVRoAN2/LRHbRYB987I3+3rDuGwGTWNfuQeAJgGl8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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