SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0941c11029d0c91c166cb288e64d50e4255dabebb801053d416546471fb1459' 
  AND token = 'LCESacfKj12vwzFWrpy4lh7ecILA0pOwCuDAjzz6kPw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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