SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8738c7dc44b2c9a431e0c9c3e3bef7031c568c5652c9678eea30484f03bf782f' 
  AND token = 'e/4zttf27GYvXKFovjbjvBuOyUftKLP52+wCVT1o62M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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