SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd5d64d886c2ef8ebf56a1a832b8d5d2b07b2c84d584013781aa1278c765eaac' 
  AND token = 'ibvNJwkbhwPS51jpVfcGe5PkNsjVU+53vkUX9h+ZOYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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