SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd798f5f5db26ab8323f4ac03279101e1896207c3c222a27aaa297b5f6f83d74' 
  AND token = 'KqfPYUL845aPZu3UAWzAjzmSXV2pXv6eZIGH3wcfiig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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