SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '329e609b2216b079bbba40caf2cb38bd6e1919be31865765adc4aca274b286e7' 
  AND token = '+fT7tsYoPvfuIXYa+CKGvXQkFnPQwIsREMMvPlLxQhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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