SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfac109ee250d8c1b54293f57e3d9d90a066914742b0c0e8c63bb87494e100d2' 
  AND token = '7JEp/9Ki8T48OJmZuxvHx292pcMcZ3BuU1bEonkLcRU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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