SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ada18a4f194108fc083eb2168281733c88d3f36743f98b32f16d1d8a1ca5ee42' 
  AND token = '0tNCoTfG8Wl3AxTc5ypF9Dc4rnAC1XmYjqIXIpufck0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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