SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '116a6fb6275a530c92a3c2681e57bd5fb7b870626aa4657555a47d4753cce904' 
  AND token = 'dyKvN5AXGg9GLC+HyjQ2UUyvTphEKA5duLO2/mmwPBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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