SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7b26fee2d9491bc5e41d9dbef945c3e5ebd3795e57f8eb1f9970c62f78ff2da' 
  AND token = 'OvQ74tXa8ze++UG7J84fC5wWstVJrXK9DYnAR1ywWC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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