SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b96490726251bde3c2aac91f215fcd0e04d4927b582bba9575dad86439275109' 
  AND token = 'rz0kwrN9rR903dNRbTrODnGWNg1OcxbEVZ/cLnDQen0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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