SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efbce02aa8c93013892f22819cc2ca324928aa7919e5caa25c9cfffa97af35ee' 
  AND token = 'nhmGEmRKIPbDLH/E1vjQIyp8fSWzIvWkCFBCg3Nl980=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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