SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '393ba55728f93d1a62d95d746af795ce568637a5ac6706246771245dd767e3c8' 
  AND token = 'vpmw3ya9UfDPOOjWt5FpTvJPQ54BwLexjgLH14IVut8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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