SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69d0bba6907c1de2e46fa019835d14da0b7cf91c8d406613f2afc6e84feda13d' 
  AND token = 'yRhv+9HMcYuf4NrEbOiDuiir/gnO04MQJwN/7nIqXAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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