SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74df40d58ea5d08e5593ceaee4e0ddfe910659057a27db573a6f0e7dcc9fff8d' 
  AND token = 'le8H7MEKgfVQB9WUVmQlEneec5py8Lw/zgTrLm7jzMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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