SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6b63da70fb8cd697da6601f91b07c8b75743bc291334df87c2311b40fac33a5' 
  AND token = 'bksWQpZ/awPAY/TfbbtyQ6EY8bytrENLYVOurPmRbgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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