SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a111a77354aa0751d07bbd64c36cdc3cf6f51447563960409b6da5ce48658071' 
  AND token = 'BEr2S86xmbcBqWQww2BCfSBsvgMBGWvcDULN2fZFdpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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