SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '99dbbe5640e3f78a14a570603b5a5dda7271d0a0914a8623992638109a0387c9' 
  AND token = 'DAH0dTUL5wNXFOj9I/K0BGt2EUM73MwRZPxwrQ5HxGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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