SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'eadf3801606818572ec8f76a334eb54ba796aac64975f4871c034887f1223b51' 
  AND token = 'IbcjZ1U+uU+YeslP1XSmhkjfoRtzuwiFet5N37/WowQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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