SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa4d21c8cb828f18e7ee2cf321130de053a6c90b458616c172be9a638571f23a' 
  AND token = 'ZlZ95tBlm6A3OD0HolpCpvdWiAZj0moANci6+qaODuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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