SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '593ebb64bcf7d0f4fb94e92feeb259bb9ba30576df5c282ae8213cbbff3a0f69' 
  AND token = '3Uh/ZjRvS6mErikdfhLxizifS906aH+itxWJ3TtgXO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}