SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38cc0654dfefebf54a698fef384a6fc3edec08654d7808a23b2dcf815ee24f5b' 
  AND token = 'N2Pftvos/Oh6czdEQBrNpualpu9BkUshp9+bAAqc1oY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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