SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f7bde238017293f98bc3e814738f626bae204f9edfb48dba19c3dd5feb8652c' 
  AND token = 'j+NMXZRybnXFX7tynAeM5AjaO4GGeC/EodBKoWHpPZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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