SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8eaf6eeab95a0b438e38b3073733c4bbaebb84fe7fef3f97910b649676239e9' 
  AND token = 'bi7b/yKCmBZ0lKh+BoIzsCK0yT6vIci5O0dInJHD2tE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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