SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74d1b92522cd00e8b890dc29eaf2f15ea879ecbebeba408b47c7aca5115213c4' 
  AND token = '9JGOxyVftHu2QVC+QCqS9ECmpxxuVtRv/MdEtjqnAH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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