SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84fbc7a4168e9d065808b4e0ba21c1098ee20650bb5bb93f097d5ccfe8524cec' 
  AND token = '29enpZqf1URGp+mo8IU5GqzGzWmyTeo+mn1wW6dmDhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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