SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9348e20f3df23201abfa68df8706caeb05c2fde150fc2d898878f18bbea15a6' 
  AND token = '2CVA2rSr/K72mIetR3wP7zxh5nhZfB1lr1jB/rgw3qI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00094

JSON explain

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