SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39b1ef6e1be01fcbac7fb370cab2b0090d71b3b8d067072a54a6d00b9e417188' 
  AND token = 'eTQCEtdoszM1PAze28vvn3GaCbzxIWnPVSbrzgnBYdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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