SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f1470acc467bf4d2c6b482d55c547482e57190da0ba33cb2a90409be1f03a2f' 
  AND token = '3Mlz1AtTvJB1VPWslGtsfv9U1nbhtpJ6FHS4/eE2jbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}