SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cae8068dfeee1651dae724791e486e577991e05963ffbd7da104499ee427ed4' 
  AND token = 'mzJgDPbKqSorIclEp7owO7Y+fl/e2N5Hhv//9/sSoWo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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