SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '397daa13b1adfd720fb11f4a49b80979134dea2156c305d8859f2c46d4244f18' 
  AND token = 'G27cofdi0oMc7YMU4MbQlzCGXSlMUN8rFEOcXWeltdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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