SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3387436bcdf72c768da7e674d4123fae2dd1efee98f0942ba7ed382fe5cccd0' 
  AND token = 'Obw1KpZpb4GiwprgQt9WFzFgS3Mj+g/VkHuh68Y5ysw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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