SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c93b40b6bd0292fbabcadacb3a1142a8ba004e77cb51c1dadf6e5e920a26770' 
  AND token = 'GLBshnGwIy8+usVAqUNmxZWZJ0pmLnzEwVW3v3ndQbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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