SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '558fae6b0833683fa32f6341900352f849364415a74873d18f8c900a179efeae' 
  AND token = 'rDDGS9JiNXpXj/jGJ+3gKuhhhWTIKQ7qoE/W4cVI5V8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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