SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6400ca632a507c885686969edc26b6523b9922838483e1b8b17ab86d3393aff4' 
  AND token = 'SBEsYr1nOlnErgFYjUoDw0H5h/gdLEyGT4CIROnAKZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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