SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20795d19bad8bdff9f390e732e51f5e6623d252354491ac79318a32d00de0526' 
  AND token = 'n8z518sKiJUZlKoSfbt7kbfrfPlJh2Fcd8nCq8eVxFs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00070

JSON explain

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