SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '766eb76132dffdbc8396d3977b6396ee148158d64c17d83c581e8a0abea95bd0' 
  AND token = 'a2ABiL/wGKZkZfYr0a9yG9nmhPAXWTgUJ+dvSCyY40E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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