SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78a9750a2d35f909694ac1c7a64efd8a876805b903734bff6bde5e5428998b1e' 
  AND token = 'cGMPA8woy2EwlYszCZJ2ZjPFOnX1R4EGgfZAADl5Y/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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