SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28808537c36fe85548a3c5438fb96d1cd51ac3761c7218023d5160ec494745d1' 
  AND token = '4xCu1sgP0ZcwnEkNwnsXog2imEJdjIonVQM4WUynVKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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