SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6550124dc90bb279acaa79edb82c876afa72c80537ef7de70b9340fb8ef004a0' 
  AND token = 'G1EounOK8Of8WQTE8cpXmJTpgYtAl3YiK5MtDMqozus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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