SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f766ca03ffe7e8100ce4f98661832371df35d120ae5952d54c681ab4d3614dcc' 
  AND token = 'I/HmvOAuhmcvTJFcdgT6jGwFMfBARyHX5qmlWR5IKlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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