SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2037f6c04cc341d40018625c220287e15d2864f07793f648d61e18fbec3522ca' 
  AND token = 'g6Uz+uA0UDuf33CMQUrHMQvBGCGoGdUO+12XJq/yLUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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