SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78a9f32b6def732ad433714bcb569de9f60b3f941eb0284946dd8a0a665b724b' 
  AND token = 'y7uIxxN3j8lArgvXZXqouXdPAXmwQy/tpmieE5n0grc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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