SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6e7732c73c39d1e2bfbaf31968cd1c0208d296a439491d692400924b0c6eb02' 
  AND token = '33aQyC2R8Vui2r58+pRx2OyFSPD+AQkMWL/i2cQKGd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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