SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f2f7786e4b7871487207d9095a2bdd3cd8756426bd3971b0553398d57ea99e5' 
  AND token = '1oCZvtkFzV0lJFsoWZDlG4EuH1FiUWqUdbQawxNDHzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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