SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b81ad57a6b48460d0b9f0941e11cd7ccd7023eb4d0c93537330cca88fef6c6dd' 
  AND token = 'IxbCPi86IzstC3isFqH1nTDrSUETpWCA1rUGYpwiss4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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