SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c53245b5d62590b8b6fba9056801403e25800ff84c96c9fb8af3c79a088ca1a8' 
  AND token = 'BstsKdpDZzCEO/xRG6M7JCZlHG2wmI2r4v22fu1BusQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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