SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a6b6dcbab84b922feacd7ddbea483fff04a468a9f1d87a5969f4ab315c628b2' 
  AND token = 'l/FzF4d2co7UaVw3uTVLJnXdzOAT7nmLgYKoshXNJuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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