SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '542da347a0c742263d926c117e21e464a096b2147a5b19e3913095c4e236740c' 
  AND token = 'r4lPcaiEVQYekgUMlNA3baivbzrQN84I1ugRomw+lTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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