SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3383b65ad8ec404010b7d112c79cc3404818dca2ada3cded13474080505fefa9' 
  AND token = 'A6mkDfq0OG8pzgS+BGVBjKfYIMRPX0mPJHIRPrb8K/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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