SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb63853df21ab4a11c66c2b5c89c009f8f74a318516e957f9f20adeebabc0ea1' 
  AND token = '2MZlnKjvDMZP44cM8az6gIGATZOE1Y/IVWGTC9VWnUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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