SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '747c4773ff71296c07a44794eda4fdf6791311ff83102dd5da1b1f9101d6ea49' 
  AND token = 'YVP7Kw0F9QLCUzknHPkJ4CxtL+Ad8pTys6E3ixxhHFw=' 
  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"
    }
  }
}