SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79c2d1620a77419b219f8a1be0a9d84cf10b2d953ba469c7a5759fe787523441' 
  AND token = 'HQu1hRkqJmWMDwl+OhYr7fK6o6EQ3UFBFIszwhSGID8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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