SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd344509debad3ca91501cceecb4f8f0dfb92470edafaad3f0c5dc3f44729c3ea' 
  AND token = '856Wyv0Gc1JAyiSGUqHuTHCIqa7OgyWM2esaebyMKAI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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