SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c9c7aa0c3ccd2782f618a7a2ee880ea2bca738c62022bd9ed573c1810bf390a' 
  AND token = 'qOfYKaz+BZ7BvRkSeyvS2sVvGG709KKkyhNUB35amyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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