SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8236d494621b186f5d99bdfe5991b97f467fe63982c7b0c0150f256ffd085cd' 
  AND token = '+W9bXbZ1XmPjrdpGaczjjbB+1b4GpmaINdLuZbVQizM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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