SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14e73c023962f1c379bba71e4bbbe36f40e03401c8ab9ba92194010e352d7957' 
  AND token = 'u4ssKaGneERJpWFFU8uMJxPTAiG9twpDZGTqrkIHUvg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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