SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcf3fe350094d1a7cce7e792f7d49a4c8908e4b59bebc71578ef6c973d3f7eb3' 
  AND token = 'ONNbC8JghsHNC96bSHMr6bBSfbgAjrRXTAxNX7/eZMw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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