SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b50db71eee3e8f16a193796f4999a375f3e394f35aa6dacdef633316a9d8b392' 
  AND token = 'Ejqtu0B81LxC6Bc3qSEC6sMCMMKgS/ez1Q5isycvBjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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