SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9da06b2476f2f025665aeb10c786645169d5275ac433822e0d51e2b8ed9aba84' 
  AND token = 'fPfkbarmVMrHvhFboWRXwNu0A1ph9RoTLwVKKuSclDg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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