SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffd60982724ab795cd67467c1f2709cb28075dcb92662e3b613f957601598df4' 
  AND token = '47ZAn5jr4fLgmQ0eGPsxFyZeVQEl0UurxgANjhgxJrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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