SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91f97569abbe87cb490db36c5b2470aaca8994ffb0af07d607590f19c176c605' 
  AND token = 'AerxIAOakuMXJi4MnqdqNf3yoYNIxSBcIQ7Rvn0uncs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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